Breast pumps are well known devices for extracting milk from a breast of a user. A breast pump may be used if the baby or infant is not itself able to express milk from the breast, or if the mother is separated from the baby or infant and is to be fed with breast milk by someone else. The use of a breast pump to express milk may also be used to stimulate and increase milk production in women with a low milk supply.
Breast pumps make use of a negative pressure to induce milk expression from a nursing mother's breast. The pumping action of the device draws the milk from the nipple to a collection vessel, and the pressure and/or frequency may generally be adjusted to the preferences of the user.
A known breast pump for extracting milk from a user's breast is shown in FIG. 1. A breast pump 1 typically comprises a main body 2 with a rigid breast receiving funnel 3 connected to a vacuum pump unit 4 having a collection vessel 5 for collecting the milk, such as a feeding bottle or bag.
The breast-receiving funnel 3 extends from the main body 2 for receiving the breast of a user. The funnel 3 is generally frustoconically shaped and comprises a mouth 6 and a neck 7. The mouth 6 is open at an outer end and an inner surface 8 of an outer funnel wall 9 converges from the outer end towards the neck 7 to form a hollow cavity in which a user's breast is received.
A fluid path is defined by the mouth 6 and neck 7 of the funnel 3 and extending through the main body 2 to the collection vessel 5 so that milk expressed from a user's breast flows along the neck of the funnel 3, through the main body 2, and to the collection vessel 5.
Research has shown that when a baby is feeding at its mother's breast, it applies a peristaltic type of pressure to the mother's nipple sandwiched between its tongue and the roof of its mouth when it sucks on the nipple. This peristaltic pressure on the nipple draws milk from it. When the pressure is released, e.g. as the baby takes a breath or swallows, a new supply of milk flows into the nipple ready for a baby to extract it again once the “let down” reflex is activated due to the mother's “oxytocin” release.
Flexible resilient cushions or inserts are known which fit into the rigid funnel portion of a vacuum generating breast pump and have protrusions on them which massage the user's breast when a negative pressure is applied thereto. Such an insert is generally formed from a silicon or thermoplastic elastomer (TPE) in an attempt to improve a user's level of comfort and aid the expression of milk. An insert is described in the earlier filed European patent application 96301046.7.
Such a known insert 10 is shown in FIGS. 2 to 4 prior to insertion into the rigid funnel portion of a known breast pump. The flexible insert 10 includes a conical mouth portion 11 which is connected to a tubular inner portion 12. An outer surface 13 of the flexible insert 10 is configured to lie against the inner surface 8 of the rigid funnel wall 9 when the insert is disposed therein. The insert 10 has a plurality of axially spaced deformable recesses or pockets 14 formed in the outer surface 13 of the mouth portion 11, each recess 14 forming a vacuum chamber with the inner surface 8 of the funnel wall 9 when the insert is disposed therein. Each recess 14 has a channel 15 extending to a rear end 16 of the inner portion 12 to communicate each recess 14 with the tubular inner portion 12. Five recesses 14 are shown in FIGS. 2 to 4 arranged circumferentially around the mouth portion 11 and spaced from each other, each having a channel 15 extending therefrom to the rear end 16 of the inner portion 12, so that inlets 17 to the channels 15 are spaced circumferentially around the rear end 16. Therefore, when a user's breast is disposed in the funnel and locates against the inner surface of the insert and a negative pressure is cyclically formed by the vacuum pump unit 4, a negative pressure is formed in each recess 14 and the insert wall of the recess is caused to cyclically deform and deflect towards to the inner surface of the funnel wall causing them to move inwardly and outwardly relative to the user's breast in an attempt to massage the user's breast.
However, milk expressed from a user's breast into the funnel of the breast pump is known to pool in the funnel, against the insert, in particular when a user sits back in an attempt to relax and aid the user's “let down” reflex. Therefore, a problem with known breast pump arrangements is that milk pooling in the funnel lies against the insert and is able to flow along the channels communicating the recesses with the rear end of the insert, and is drawn into the channels due to the cyclical pressure generated. As a consequence, milk is known to flow between the insert and the inner surface of the rigid funnel wall and into the petals which will reduce their effectiveness at massaging a user's breast. Furthermore, milk can visibly collect between the rigid funnel wall and the insert, giving the impression to the user that there is a problem with the product or that it is leaking. In addition, milk may also leak out of the breast pump, between the funnel wall and the insert, and onto the user's breast or clothing causing discomfort to the user.
Expressed milk is considered to be very precious and is known to have a high emotional value to mothers that have expressed milk from their breasts. Therefore, this residual milk collecting between the funnel wall and the insert and leaking from the funnel is considered to be a loss to a user because the milk cannot be useably collected, and this loss of milk may have an emotional impact, such as a psychological loss, disappointment or distress, on the user.